Preparation And Performance Of Copoly(Phthalazinone Biphenyl Ether Sulfone)hollow Fiber Membrane

Hemodialysis membrane is the core of hemodialysis treatment,which plays a decisive role in the quality of dialysis treatment.Polysulfone are widely used in hemodialysis membranes due to their good thermal stability,mechanical properties and film-forming properties.However,polysulfone hemodialysis membranes still have poor hydrophilicity,easily attenuated flux during dialysis,low molecular toxin clearance and other issues.Therefore,it is necessary to develop hemodialysis membrane materials with more excellent performance.From the perspective of molecular structure,copoly(phthalazinone biphenyl ether sulfone)(PPBES)with different structures were prepared.PPBES hollow fiber membranes were prepared to explore the effect of spinning process and polymer structures on PPBES hollow fiber membranes’structures and performances and simulated hemodialysis experiments with lysozyme and urea to simulate small and medium molecular toxins in blood were used to initially explore the application of PPBES hollow fiber membranes in hemodialysisIn this paper,PPBES were prepared from 4-(4-hydroxyphenyl)-2,3-phthalazin-1-ketone(DHPZ),biphenol(BP),and 4,4’-dichlorodiphenylsulfone(DCS)by nucleophilic polycondensation with different proportions of DHPZ and BP.The ~1H-NMR and FT-IR analysis of PPBES with different structures were performed to prove that the expected product was synthesized.The cloud point titration method was used to study the thermodynamic stability of PPBES solutions.The experimental results showed that as the content of the phthalazinone structural unit in PPBES increased,the thermodynamic stability of the spinning solution decreased.PPBES with different structures were used as the membrane material and hollow fiber membranes were prepared by a non-solvent induced phase separation(NIPS).The experimental results show that with the increased of the phthalazinone structural unit in PPBES,the finger pores of the hollow fiber membrane gradually disappeared and sponge pores appeared.The inner and outer cortical layers of membranes became loosened.The hydrophilicity of the membrane was improved and the porosity was reduced,and the flux recovery rate was improved.The rejection of bovine serum albumin(BSA)by hollow fiber membranes were all greater than 93%,pure water fluxes were all greater than 23.9 L/(m~2·h),and the breaking strength of hollow fiber membranes was greater than 6 MPa.Among them,the pure water flux and BSA flux of PPBES6040 hollow fiber membrane were 34.5 L/(m~2·h)and 25.5 L/(m~2·h),respectively,and the flux recovery rate was 68.4%.The clearance rates of urea and lysozyme were 37%and 32%,respectively.PPBES6040 was selected as the membrane material,and the effects of additive concentration,polymer concentration,and air bath distance on the structure and performance of hollow fiber membrane were investigated.The experimental results showed that as the additive polyvinyl pyrrolidone concentration increased from 1 wt%to 4 wt%,the finger pores of the hollow fiber membrane disappeared,the structure became denser,the flux recovery rate increased from 64.0%to 83.9%,and the water flux decreased from 33.6 L/(m~2·h)to 12.9L/(m~2·h),the rejection rate increased from 94.2%to 99.3%,the clearance rate for urea decreased from 34.5%to 20%,and the clearance rate for lysozyme decreased from 27%to12%;as the polymer concentration increased,the structure of the hollow fiber membrane became denser,the water flux of the membrane gradually decreased,the rejection of BSA increases,the porosity and hydrophilicity decreased,the flux recovery rate of the membranes gradually decreased.When the polymer concentration increased from 12 wt%to 18 wt%,the clearance rate for urea decreased from 41%to 29%,and the clearance rate for lysozyme decreased from 35%to 22%;as the air bath distance increased during spinning.The finger-like pores of the membranes gradually increased,the outer surface of the membrane became denser,the pore diameter and the number of pores continued to decrease and the hydrophilicity of the membrane decreased.When the air bath distance increased from 15 cm to 35 cm,the flux of hollow fiber membranes decreased from 35.9 L/(m~2·h)to 23.5 L/(m~2·h),the retention rate of BSA increased from 90.2%to 97.5%,and the flux recovery rate decreased from 89.1%to 73%,the clearance rate of urea by membranes decreased from 39%to 25.5%,and the clearance rate of lysozyme decreased from 34%to 24%.